Rockspring and Sterling Property have apparently acquired the Natwest Tower site in Birmingham.
The vendor was British Land and the sale price is estimated to be £15m.
103 Colmore Row site will deliver 220,000 sq ft of grade A office space when construction is completed in the middle of 2017.
The site covers half an acre of prime city core real estate and currently comprises a 24 storey office building.
Work will commence on site in Q1 2015.
British Land was represented by Savills.
Rockspring and Sterling property Ventures was represented by Colliers Internationals and Knight Frank.